The background to this technology is described in our U.S. Pat. No. 6,951,158, and will not be repeated here. U.S. Pat. No. 6,951,158 showed a tool to engage a screw head. This configuration had advantages in that it restricted the screw from wobbling, and prevented the driving bit from camming out of the screw recess. However, the tool and screw head could not interact so that the screw was ‘stick-fit’ and retained on the tool without the possibility of falling off. The tool engaged the screw head within a hexalobular slot with surfaces that were directly parallel to each other.